Which controversy involved a dispute over the phrase added to the Nicene Creed regarding the Holy Spirit?

The Filioque Controversy pertains specifically to the phrase "and the Son," which was added to the Nicene Creed regarding the procession of the Holy Spirit. This addition sparked significant theological debate between the Eastern Orthodox Church and the Western Church (Roman Catholic) during the early Middle Ages.

The original Nicene Creed, established at the First Council of Nicaea in 325 AD, stated that the Holy Spirit proceeds from the Father. The Western Church later adopted the Filioque clause, asserting that the Holy Spirit proceeds from both the Father and the Son. This theological distinction carried implications about the nature of the Trinity and ecclesiastical authority, contributing to tensions that would eventually lead to the East-West Schism in 1054.

Understanding this controversy is crucial because it highlights the theological differences that have historically divided Christianity, illustrating how doctrinal disputes can influence the broader context of religious and cultural divisions in Western civilization.